THE EURYPTERIDA OF NEW YORK
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In tabular form the character of the three stages and the changes are as follows:
Nepionic Stage | Neanic Stage | Ephebic Stage | ||
Carapace | Large | Decreases in relative size | Continued decrease | |
With broad border | Border becomes narrower | Border more or less narrow and obscure | ||
Compound eyes | With immense visual node | Visual node small | Visual node small | |
Position submarginal | Submarginal | Subcentral | ||
Visual surface relatively small | Visual surface relatively small | Visual surface relatively large | ||
Abdomen | Segments 7–8 | Unknown | 12 | |
No distinct differentiation | Distinct differentiation | |||
Preabdomen | Regularly narrowing posteriorly | Widest at fourth and fifth segments | ||
Postabdomen | No epimera | Long epimera | ||
All segments equally long | Last segments much longer | |||
Telson spine | Very short and blunt | Long and slender (?) | ||
Sculpture | None | Tubercles | Tubercles |